Signal.



Patented Apr. l7, I900. F. L. DODGSON.

SIG NA L.

(Application filed Oct. 29, 1897. Renewed Mar. 22, 1900.)

No Model.)

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NITED STATES PATENT QFFICE.

ASSIGNMENTS, TO THE \VEST VIRGINIA.

SIG

ASSIGNOR, BY MEsNE SIGNAL COMPANY, or

NAL.

SPECIFICATION forming part of Letters Application filed October 29,

To all whom it may concern.-

Be it known that I, FRANK L. DODGSON, of Rochester, in the county ofMonroe and State of New York, have invented certain new andusefulImprovements in Signals; and I do hereby declare the following to be afull, clear,

and exact description of the same, reference being had to theaccompanying drawings,

forming a part of this specification, and to to the reference-numeralsmarked thereon.

My invention relates to that class of pneumatic devices, such assignals, adapted to be operated at a distance from the controlling pointby means of compressed air or other I fluid under pressure, and has forits object to provide for the rapid operation of such signals by a veryslight alteration in the pressure. Heretofore in devices of this natureit has been customary to operate signals, more particularly the distantsignals or semaphores, in one direction by the admission of fluid underpressure to the main pipeor conduit leading to the signal and to operatesaid signal in the opposite direction by reducing the pressure in saidpipe, but the length of time required to vary the pressure at the signalby a variation at the controlling-point is often too greatto cause theprompt action of the signal which is desired.

NVith the object in view, therefore, of cansing the prompt action of thesignal the present invention consists in certain improvements wherebythe signal is operated directly by fluid under high pressure availableat the 3 5 signal or other operated device, the valve devices forregulating the admission of said fluid being controlled by adifferential valve, which latter is in turn actuated by fluid underpressure in two' separate mains or conduits under the control of theoperator at the controlling-station. By this means the auxiliarydifferential valve controlling the main signal-controlling valve maybeoperated positively and quickly by slight variations in the pressure inthe two pipes under the direct control of the operator.

The invention further consists in certain improvements in constructionand combinations of parts, all as will be hereinafter fully described,and the novel features pointed out the end of this specification.

in the claims at Patent No. 647,719, dated April 17, 1900.

1897. Renewed March 22,1900. Serial No. 9,788. (No model.)

In the drawings, Figure 1 is a vertical sectional view of asignal-operating device embodying my improvements and showing alsodiagrammatically the controlling-valve and the connections between itand the signal; Fig. 2, a side elevation of the signal with a portion ofthe valves at the signal shown in section.

Similar reference-numerals in both figures indicate similar parts.

While I prefer that my present improvements be used for operating such adevice as a signal or semaphore and have shown it in connection withsuch a signal, it is only essential that the operated device, whethersignal, switch, or other mechanism, shall embody a cylinder with apiston operating there in or its mechanical equivalent, said pistonbeing automatically movable in one direction 1 indicates a signal-post,2, a cylinder secured thereto; 3, a piston operating in the cylinder andconnected by a rod 4; and link 5 with an operated part 6 as a semaphoreor si gnal-arm,havin g a Weight 7, connected thereto, operating to throwthe arm up to the position shown in full lines in Fig. 2, indicatingdanger or normal position.

8 indicates a pipe communicating with the cylinder 2 and also with thechamber 9 in the valve-casing 10,secured to the post. Arranged in thevalve-casing 10 are seats 11 and 12, preferably packed, as shown, withwhich cooperate the heads 13 and 14, connected to a valve-stem 15.

16 indicates a port controlled by the head 14, said port opening into "achamber in the upper part of the valve-casing, with which communicates apipe 17, leading to a suitable reservoir 35 for fluid under pressure,located at the signal-post, atthe central controlling-station, orelsewhere, the pressure being practically constant. The valve-casing 10is provided with an exhaust-port 18 beneath the seat 11, and the valve13 14 is adapted to be engaged by a pin or projection 19, secured to orresting upon a diaphragm 20, arranged below it. The casing above thediaphragm 20 is provided with an exhaust-port 21 or is otherwise open tothe air, and the chamber below the diaphragm is connected by a pipe whenthe pressure inthe cylinder is reduced.

either 22 with a valve-casing 23, 'pr0vided with valve;

ing to the valve under-the control of the ops orator.

The controlling-valve 50 maybe of any'su-it able-construction by whichfluid under-preso of valve or valve devices if desired, which. willaccomplish thexsame sure from arreservoir 35 may be admittedto thesupply main or pipe-29 and the supply main or pipe: 3l' opened totheair, or when desired to operate thesignal in the oppositedirectionpressure may be admitted to the main 31 from the reservoir orother-suitable soureeand the main-29 opened to theain In grammaticallysuch a controlling-valve as is contained in my prior patent, No.513,231, dated January 23, 1894, asIfind this isrconvenient for thepurpose; butany other form could be employed,

result.- It is preferred that a single valvelbie employed; but thisisnotabsolutely essential.

As shown, the signalinthernormal or'dauger position-with thepistonSv atthe end of the'cyli'nder, the valve-14 isuponltheseat 12fand is heldbypressure'of the fluid in the chamber in the thevalve-casing, thecylinder being'open to theairthrough the exhaust-port 1'8, and both themains'29 and 31 are open to the air. In order to operate the'signaltothesafety position it is only necessary to open the m'ain. 29

'tothe air and admit fluid. under pressure to the main 31, and saidfluid will pass thence through the pipe 22 to the chamber beneath thediaphragm20. Then by reason of the difference-between the areas of thediaphragmandthe upper end of the valve 14 the fluidpressure against thebottom of the diaphragm will raisethe valve-heads 13 and 14, closing theexhaust-port 1'8 and opening the port L6, admittingfluid from thesupply-pipe 17 to the haust-port. 18 h'aust of th-efl'uid from the pipe8, when the 5 weight or counterpoise counected mediatelv beneath thediaphragm mal position this meansa is-obt-ained, as I find in practicethat the employment of the two difierential valves, one

or. operated device; is larger area, it will upper part of I 26 from theseat 25 will permit the escape of the airfrom the pipe 22 through theexhaust 30, allowing the diaphragm 20 to be moved down quickly bythepressure upon the valvehead 14, connecting the pipe 8 with theexand'permitting the quick exwith the piston will return the latter tonorat the top of the cylinder. By very quick action of the signalcontrolling the supplyof fluid directly to the cylinder and the. othercontrolling the supply of fluid to the larger area of thefirst-mentioned dilferential valve, insures the positive operation ofthe distant signalinv a small fraction of'the time required to exhaustthe air from a long. continuous pipe or toreduce the pressureatt'he farend thereof to a suflicient degree ,tocause the actuationof an: ordinaryvalve.

The. arrangement whereby the fluid is ad mittedto-the larger areaof thelower control the present embodiment I have shown d'ia- 1 ingdilferential valve to cause the opening of the cylinder to the air isadvantageous, as

' theoperation ofthe signal to the danger pdsition is'insured, even ifthe same amount of 'pressurewere contained in the supply-mains 29 and 31or th'eima-in: 31- shouldfor any reason become stopped up.

WhileI prefer toemploy diiferential valves embodying diaphragmsconstituting the beunderstood that pistons operating in cylinders couldbe readily em ployed. 1

I claim as my invention 1. The combination with the cylinder and thepiston operating therein,a reservoir for fluid'under pressure adaptedfor connection with the cylinder, and two main pipes to which fluidunder pressureis admitted alternately, of a differential valveactuated-in one direction by the flu-idfrom: the reservoir and 1nder,.and a difierentialvalve between the two main pipes controlling. thepassage of fl uidr to and from one side of thefirst-men- -tlioneddifleren tial valve, substantiallyasdescribed.

2.. The combination, with the signal arm the piston connectedthereto,the cylinder,

the supply and exhaust ports therefor, two valves, the first controllingthe supply and 'exhausttolthe cylinder, and the second; connately. g I

3. Thecombination with the weightedsig piston connected thereto,

halt-arm, the

controllin g the supply-and exhaust to thercylthe cylinder, the supplyand exhaust ports for the cylinder, a reservoir for fluid underpressure, a valve operated by fluid from the reservoir in a direction toadmit fluid to the cylinder, and a diaphragm for operating said valve toopen the cylinder-exhaust and close the supply-valve, of two mainfluid-supply pipes, valve devices for admitting fluid under pressure tosaid pipes alternately, and a differental valve actuated by a differencein pressure in the supply-pipes, the valve being actuated by pressure onthe larger surface in a direction to cause the opening of theexhaust-port of the cylinder, substantially as described.

4. V The combination with the signal-arm and a weight for turning it tonormal posi tion, the piston connected thereto, the cylinder having thesupply and exhaust ports, a reservoir for fluid under pressure, and adifferential valve for controlling the supply and exhaust ports andmoved in one direction by pressure from the reservoir, of twosupplymains, valve devices for admitting fluid-pres sure to the mains,adifferential valve actuated by difference in pressurein the mains andcontrolling the operation of the first-nientioned differential valve,and connections between the valves and mains whereby pressure in themain connected to the greater area of the second diiferential valvewilLcanse the opening of the exhaust-port in the cylinder and permit thesignal to return to normal position, substantially as described.

5. The combination with the cylinder and the piston operating therein, areservoir for fluid under pressure adapted to be connected to thecylinder, of two supply-mains for fluid under pressure and twodifierential valves actuated by variations in pressure in thesupply-mains, one of said valves controlling the admission of pressurefrom the reservoir to the cylinder when pressure is applied to itsgreater area, and the other always causing the exhaust from the cylinderwhen pressure is applied to the greater area, the greater areas of bothvalves being actuated by an increase in pressure in the supply-mains,substantially as described.

6. The combination, with the signal-arm, the piston connected thereto,the cylinder, the supply and exhaust ports therefor, apneumatically-operated valve controlling the suppiston'operatingtherein, a reservoir for fluid under pressure adapted,to be connected tothe cylinder, the two supply-mains for fluids under pressure, and twovalves actuated by variation in pressure in the supply-mains, one

of said valves controlling the admission of fluid under pressure fromthe reservoir to the cylinder when operative pressure is applied to thevalve from one supply-main, and the other valve causing the exhaust fromthe cylinder, when operative pressure is applied to said valve from theother supply-main, each valve being actuated by a change in pressure inthe supply-mains substantially as described.

8. The combination, in a pneumatic semaphore, of a pivoted semaphore-armhaving a counterweight tending to raise said arm to indicate danger,acylinder placed above said arm, a piston in said cylinder provided withconnections to said arm, and a main connected with the cylinder foroperating the piston by fluid-pressure to depress said arm to indicatesafety and upon reduction of pressure therein to permit the arm toreturn to indicate danger.

FRANK L. DODGSON.

Witnesses:

F. F. CHURCH, G. A. Bowl.

